Ibis Ripley

Ibis

DESIGN GOALS OF THE RIPLEY 29
Our goal was to bring the advantages of a 29” wheel to a lightweight, nimble and fun trailbike. We think 120 mm of travel is the sweet spot for a snappy bike that isn’t cumbersome or heavy. We also wanted the Ripley to be configurable for a wide range of terrain and riding styles, so we made it compatible with 120–140 mm travel forks. We asked Dave Weagle (Mr. dw-link) to give the Ripley pedaling efficiency, XC-like acceleration and optimization for 29er specific gearing in addition to the usual dw-attributes such as excellent small bump compliance, predictable travel through the range with no wallowing or harsh bottom out. This version of the dw-link, like the ones he’s done for us in the past, delivers on the promise.
THE RIPLEY DESIGN
Designing around 29" wheels presented a new set of engineering challenges. Here are some of the questions we asked ourselves as we started the design process:
How do you make the geometry feel snappy, but maintain toe clearance in the front and an ample tire clearance in the back?
How do you keep the front derailleur from hitting the rear wheel?
Where do you fit the suspension linkages and shock (while maintaining a short wheelbase, low weight and high frame stiffness)?
Can you design the frame to be both light and stiff, and withstand the higher forces of the 29” wheel?
Can we have a super low standover height but still accommodate water bottles?
What is the optimal amount of travel for a 29" bike that will be as versatile as the Mojo SL-R?
How do you accommodate the different gearing needs of a 29er whether using a 1X, 2X or 3X drivetrain?
Where do you put the head tube with a fork that tall and keep the bars in the same place?
Here’s how we tackled those questions:
ECCENTRICS
The heart of the Ripley is its dual-eccentric dw-link suspension. Instead of using external linkages like we do on our longer travel bikes, we were able to construct the Ripley with two small eccentrics, hidden inside the seat tube, which act as the suspension linkages. This clever system was conceived by Dave Weagle (he’s the dw in dw-link) in 2005, and we started development of the system in 2007. Since then, we have been building, testing refining, racing and simplifying the eccentric system. We had been developing a system with angular contact bushings, and at the same time we were developing a more traditional bearing version. In the end, the traditional bearing system was chosen for production for a variety of reasons.
The system that we finalized has fewer parts and uses readily available bearings. Along the way we kept reminding ourselves about one of our favorite quotes:
"Everything should be made as simple as possible, but not simpler."
― Albert Einstein
We feel that we succeeded.
There are many benefits to an eccentric linkage system. Because the bearings are located inside the seat tube, they are shielded from wheel spray and contamination. The look is very clean, as everything is hidden inside the frame. Additionally, the eccentric system is lighter than our external linkage systems.
A great benefit, particularly on the 29” platform is that the eccentrics let us build the bike with shorter chainstays, giving more room in the tight area around the rear tire and front derailleur.
Though the linkages are small and close together, the eccentrics allowed us to make a right side upright between the front of the chain and seat stay, resulting in added stiffness, critical for the larger loads of the big wheels. Not only that but we could mount the front derailleur to it so that it would move with the swingarm. This meant the chainstay didn’t have to be dropped to provide front derailleur clearance at bottom out. This is particularly important with the smaller gears that 29er’s typically use because you don’t want the chain dragging on the bottom of the chainstay.
All in all, the eccentrics were a huge challenge that resulted in many nice benefits. Here’s an exploded view.
www: Ibis Ripley

Posted in 29er, Carbon, Mountain Bike, Trail, XC.